Why it matters ... Parscale: "Twitter is how [Trump] talked to the people, Facebook was going to be how he won."

Parscale says he used the majority of his digital ad budget on Facebook, which were particularly efficient in reaching the rural vote: "Facebook lets you get to…15 people in the Florida Panhandle that I would never buy a TV commercial for."

Infrastructure proved to be a powerful theme: "I started making ads that showed the bridge crumbling … That's micro targeting … I can find the 1,500 people in one town that care about infrastructure. Now that might be a voter that normally votes Democrat."

Parscale received help from Facebook "embeds" provided by the company, who showed up to work at his office multiple days a week. He says they had to be Republican, and he questioned them to make sure: "I wanted people who supported Donald Trump."

Parscale: "These social platforms are all invented by very liberal people on the West and East Coast. And we figure out how to use it to push conservative values. I don't think they thought that would ever happen."